The altitude and azimuth instruments made by Edward Troughton in London from the 1790s were remarkably stable and accurate, and Troughton & Simms continued this tradition. Indeed, Frederick W. Simms ...

Is there a plug and chug way to do it if I know my barometric pressure, temp, and altitude? I need to get it everyday before I have a flying lesson. I hate using that round slide-rule flight computer ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This instrument came from the John C.